Herring was elected to the House of Delegates in a special election to succeed Moran in 2009, when he resigned his seat in the 46th District to concentrate on his gubernatorial campaign. She ran unopposed for re-election in 2011.

News4's Julie Carey described Herring as "the Democrats' point person in Richmond, [who] led sessions on reproductive rights issues. The Obama for America campaign in Virginia also used her extensively as a surrogate spokesperson [during the President's re-election campaign]."